Right-wing populist slogan turned angry men against legendary military leader (9)
I believe the answer is:
agamemnon
'leader' is the definition.
(I have seen 'Greek leader' mean 'agamemnon' so perhaps 'leader' could also mean 'agamemnon')
'right-wing populist slogan turned angry men against legendary military' is the wordplay.
I cannot really understand how this works, but
an anagram of 'men' is 'emn' which is within the answer.
'against' could be 'on' (on can mean by or up against) and 'on' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for agamemnon that I've seen before include "king of old" , "Legendary hero" , "Leader of Greeks against Troy" , "mythological king" , "Greek leader in the Trojan War" .)